Hydraulic tip type medical examination and operating tables



Sept. 25, 1956 R. L. MCDONALD HYDRAULIC TIP TYPE MEDICAL EXAMINATION ANDOPERATING TABLES 6 Sheets-Sheet 1 Filed Jan. 19. 1953 INVENTOR. ROBERTL. MCDONALD A TTOENE) I m I u I MN I o R my W C O O O O O O O O O O O a& r u fi O f mm i F V. M N MN.

Sept. 25, 1956 R. L. MCDONALD HYDRAULIC TIP TYPE MEDICAL EXAMINATION ANDOPERATING TABLES 6 Sheets-Sheet 2 Filed Jan. 19, 1953 INVENTOR. ROBERTL; M DOIVALD Sept. 25, 1956 R. L. M DONALD 2,764,459

HYDRAULIC TIP TYPE MEDICAL EXAMINATION AND OPERATING TABLES Filed Jan.19, 1953 6 Sheets-Sheet 3 7/ I 403 I28 A 107 a? 7 [27 104 -14- I Q) I yl/ A y 7'2 7 6 7 3 9'6 9/ 98 INVEN TOR. F/ 4 ROBERT L. MCDONALD ATTORNEYp 1956 R. L MCDONALD 2,764,459

HYDRAULIC TIP TYPE MEDICAL EXAMINATION AND OPERATING TABLES Filed Jan.19, 1955 6 Sheets-Sheet 4 I47 I 7' W w fi 'vw 7gb I I59 52 I53 I I53 INVEN TOR. ROBERT L. M DONALD ATTORNEY Sept. 25, 1956 R. L. MCDONALDHYDRAULIC TIP TYPE MEDICAL EXAMINATION AND OPERATING TABLES Filed Jan.19, 1953 6 Sheets-Sheet 5 INVENTOR. ROBERTL. M DONALD BY miffi w ATTORIVEY Sept. 25, 1956 R. 1.. M DONALD 2,764,459

HYDRAULIC TIP TYPE MEDICAL EXAMINATION AND OPERATING TABLES Filed Jan.19, 1955 6 Sheets-Sheet 6 H611. F aiZ VENTO ROBERT 1.. moon/AL Robert L.McDonald, Rochester, N. Y., assignor to Ri'tter Company, Inc.,Rochester, N. Y.', a corporation of Delaware I Application January 19,1953,'Serial No. 331,711

11 Claims. (Cl. 311-7 My invention relates to medical examination andoperating tables and more specifically to that type-of operating tableemployed for the most part by proctologists. However, the principles ofmy inventionmay be employed in any type of table wherein it is desirablethat the table surface be capable of being raised and lowered or tiltedwith the least amount of physical effort.

An object of my invention is to provide a medical examination andoperating table which is hydraulically controlled to either raise andlower the table or tilt it longitudinally about a horizontal transverseaxis.v

Another object of my invention is to provide a hydraulically controlledmedical examination and operating table which is of simplifiedconstruction and which removes the physical effort required to adjustthe table and position the patient as desired by a physician for'thepurpose of a diagnostic examination or operation. I f I A further objectof my invention is to provide a table structure, particularly adaptedfor use by proctologists, in which the table sections are arranged andarticulated so that what may be termed the back section of the table maybe positioned horizontally and what may be termed the leg section may bepositioned in any angular position of adjustment with respect to theback section, said two sections further being arranged and tiltablysupported whereby when the leg section is in a perpendicular relation tothe back section both sectionsmay be tilted longitudinally about ahorizontal transverse axis whereby the edge of the leg section which isadjacent the back section may be raised above the plane of the backsection and.

both sections tilted simultaneously to position the patient properly forrectal examination.

My invention further contemplates the provision of hydraulic cylindersand controls therefor which facilitate the raising and lowering of theentire tableas a unit, or-

the tilting of the table longitudinally about a horizontal transverseaxis with little physical elfort being required by the physician, thehydraulic controls being arranged so that the number of valves requiredis reduced to a minimum and the proportions-of the hydraulic cylindersbeing such that the table-lifting cylinder requires a higher pressurefor its operation than the tilting cylinder whereby when the tiltingcontrols are actuated tilting movements of the table are performedwithout affecting the raising and lowering of the table notwithstandingthe fact that the table-lifting cylinder is at all times incommunication with the pump which constitutes the source of supply ofhydraulic pressure. I

Other objects and advantages of my invention will be set forth in theclaims and will be apparent from the following description, when takenin connection with the accompanying drawings, in which:

Fig. 1 is a side elevation of a medical examination and operating tablein which the features of my invention have been incorporated, the legsection being shown in a per-' pendicular relation to the back section,one of its possible positions of adjustment; 1

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Fig. 2 is a view similar to Fig. 1 showing the table in one of itsadjusted, tilted positions;

Fig. 3 is a sectional view taken substantially on the line 3-3 of Fig.2; v

Fig. 4. is a vertical sectional view, somewhat diagrammatic, takenthrough the housing which encloses the motor, pump and part of thecontrols and hydraulic circuits for the examination and operating tableof my invention;

Fig. 5 is a horizontal view partly in section showing part of the footpedal control housing and the foot pedals for controlling the hydrauliccircuits;

Fig. 6 is a vertical view of the foot pedal control housing partly insection with the cover of the foot pedal control housing removed;

Fig. 7 is a sectional view taken substantially on the line 7-7 of Fig.6;

Fig. 8 is a view taken substantially on the line 88 of Fig. 6;

Fig. 9 is a sectional view taken through the valve block;

Fig. 10 is a perspective view showing the control shafts for performingtilt operations on the table and illustrating part of the hydrauliccircuits and how the valves are opened and closed upon actuation of thetilt foot pedals to rotate the tilt control shafts;

Fig. 11 is a sectional view taken substantially on the line,1ll1 of Fig.10 showing the position of the control shaft when the valves are closed;

Fig. 12 is a view similar to Fig. 11 with the control shaft rotated andthe valves open;

Fig. 13 is a sectional view through the hydraulic tilt cylinder; and

Fig. 14 is a sectional view taken through the solenoid valve assembly. 1

While I have incorporated the principles of my invention in a medicalexamination and operating table particularly of the type suitable foruse by proctologists, it will be obvious as this description proceedsthat the invention may be incorporated in any medical examination oroperating table. Moreover, the principles of my invention may be appliedto other types of structures such, for

example, as dental chairs in which it is desired to either raise orlower the level of the chair or tilt the chair for the purpose offacilitating an examination or operation upon a patient.

The table of my invention comprises a hydraulic system mounted in ahousing, generally indicated by the numeral 21, and a table generallyindicated by the numeral 22. In Fig. 1 I have shown the table sectionsin a position which they may occupy for certain diagnostic observations.The table comprises a number of sections which are articulated withrespect to each other and which for convenience of designation may betermed a main table section or back section 23 and an auxiliary or legrest section 24. The table further includes a head rest 26 and a kneerest 27.

The main table section 23 and the auxiliary table section 24 areprovided with guides or ways 28 which have spaced apertures 29 thereinwhich by suitable means not shown but indicated at 31, the head rest 26and the knee rest 27 may be shifted to any desired relationship withrespect to the main table section 23 and the auxiliary table section 24respectively. The particular mechanism by which this is accomplished hasnot been shown in detail since it does not constitute part of my presentinvention. However, by way of example, in Fig. l I have shown theknee'rest 27 positioned normal to the plane of the auxiliary tablesection 24. knee rest may be shifted alongthe ways 28 to accommodate ashorter person kneeling on the knee rest. Further, when the auxiliarytable section 24 is shifted to a horizontal position by means which willpresently appear,

If desired the 3 the knee rest 27 may be shifted so that it lies in aplane with the auxiliary table section 24 and the main table section 23to correspond to the position of the head rest 26 asshown in Fig. 1. Thehead rest 26 may be similarly positioned at an angular relationshiptothe main table section.

Suitable means, as indicated at 32, are rigidly secured to the underside of the main table section 23 for the reception of pivot meansindicated at 33. The pivot means 33 is adapted to receive a pair ofpivot arms 34, one on each side of the table. The arms 34 constitutepart of a cradle for supporting the table and articulating the maintable section and auxiliary table section with respect to each other.The arms 34 are extended beyond the pivot means 33 to provide tailpieces 36 which serve as stops for aiding in supporting the main tablesection in a horizontal position. The function of the tail pieces 36will be apparent from a comparison of Figs. 1 and 2.

A member 37 extends transversely of the cradle and is rigidly secured tothe arm 34 on the other side of the table. The member 37 carries pivotmeans 38 to the end of which a piston rod '39 is pivoted. The piston rodextends through end walls 41 forming part of a hydraulic cylinder 42(see Fig. 13). A piston 43 is rigidly secured to the piston rod and ismovable longitudinally of the cylinder in accordance Withthe hydraulicpressure existent on opposite sides thereof, the hydraulic fluid beingsupplied to the cylinder in a manner which will presently appear.

A'support 44 (Fig. 1) is rigidly secured to the upper end of a piston 46(Fig. 3) and has upwardly extending arms 47 to the upper ends of whichthe arms 34 of the table cradle are pivoted as shown at 48. The cradleextends toward the leg rest section 24 and the arms thereof are curvedas shown at 49. The ends of the arms 34 are partly enclosed by the legrest section 24 and pivoted thereto as indicated at 51.

Secured between the arms or cradle members 34 is a pivot rod '52. A bar(not shown) is pivoted on the rod 52 and is telescopically movable intoand out of a housing 53. A locking device is provided within the housing53 to lock the bar in a desired adjusted position. Housing '53 ispivoted at 54 to a bracket 56 carried on the under side of the leg resttable section 24. By means of a suitable hand lever '57, upon release ofthe locking device 55, the auxiliary or leg rest table section 24 maybeswung about the pivots so that the auxiliary table section 24 lies ina plane with the main table section 23. The particular means by whichthe auxiliary table section 24 is moved into a horizontal plane with themain table section 23 and the means by which it is locked in positionconstitute no part of my present invention and these parts havetherefore not been particularly shown anddescribed.

Carried by each-of the arms 47 (Fig. 3) of the support 44 and rigidly"secured thereto as shown at 58 (Figs. 1 and 2) is a support arm 59 onthe end of which a roller 61 is mounted. The support arms '59 areadapted to support the rearward end of the main table section 23 in ahorizontal position when the parts are in the position shown in Fig. 1.

The tilt cylinder 42 is pivoted as shown at 62 to a part 63 by thesupport member 44. With the parts in the position shown in Fig. 1, whenhydraulic fluid is admitted 'to the cylinder 42 at the left side of thepiston 43 as the parts are shown in Fig. 13, the piston is moved to the'right, pulling the cradle 34 downward and pivoting the cradle about thepivot 48. This action causes the main table section 23 to ride on therollers 61 so that the angle between section 23 and frame or cradlemembers 34 as shown in Fig. 'l is gradually reduced. Finally, in extremetable tilt position Fig. 2, the cushion 23- is-no longer supported byrollers 61 but is permitted to completely collapse against and besupported by the cradle members 34.

By allowing the cushion surfaceof the main section 23 to drop downagainst the cradle members 34, the cushion surface acquires a positionseveral inches below the flush line of a leg rest cushion shelf 64. Thuswith the parts in the position shown in Fig. l and with knee rest 27properly adjusted to accommodate the height of the patient, a patientmay :kneel on the knee rest 27 and bend himself at the waist so that histrunk and shoulders lie on-the surfaces 64 and 23, and his head and armsmay rest on 26 as it is brought upward and forward to be locked on metalguides 29 at proper position to suit size of patient. Then as the tableis tilted by means of hydraulic cylinder 42 to the maximum position asshown in Fig. 2, the drop-out action of the main section '23 operatesautomatically as a function of table tilt to form a recessthus relievingpressure against patients abdomen and permitting the main portion of thepatients weight to be supported by his legs and thighs against leg restcushion surfaces 24 and 64. Manipulation of the patient to this positionis much to be desired by the physician practicing proctology. Thecombination of patients head-low inverted kneeling position along withcushion drop-out which relieves pressure against patients abdomenresults in a natural and gentle pull of gravity against the patientsinternal organs so as to ease discomfort and facilitate straight lineinsertion of sigmoidoscope or similar medical instrument insertedrectally for examination, treatment, and surgery. By proper actuation ofthe hydraulic controls 114 and 116 the operator or physician may arrestthe movement of the parts, as will presently appear, secure the amountof tilting action desired, and obtain this automatic center sectiondrop-out as afunction of table tilt without further manipulation ofsecondary controls.

The "hydraulic system for raising and lowering the table is for the mostpart enclosed within the housing 21 (Fig. 4) and includes a hydrauliclift cylinder 66 which to a large extent has been diagrammaticallyillustrated. However, it will be understood thatthe lift cylinder 66 isconnected to the member 44 (Fig. l) to raise and lower this member andthus raise and lower the entire table unit. The hydraulic liftingmechanism has been only diagrammatically illustrated as such mechanismsare well known in the art. In the drawings I have illustrated astationary piston 67 and a movable cylinder 66. If desired, acombination movable cylinder and telescoping piston may beemployed toincrease the amplitude of movement of the table while maintaining theover-all height of the table at a minimum when the table is in its lowermost position.

Mounted in the housing '21 in any suitable manner is a motor "70 (Fig.4,) which drives a hydraulic pump 71 which may be of any suitable type,for example, a hydraulic positive displacement gear pump. The housing 21is supported on abase 72 in which a sump or reservoir 73 is provided. .Aconnection 74'extends into the sump and has afilter 76 mounted on thelower end :thereof, the connection or .pipe 74 conveying oil to thesuction (not shown) "of'th'e pump 71 when the pump is operating tocreate a suction in the pipe.

A solenoid valve 77 '(Fig. 14) is in the hydraulic circuit 'from'thedischarge of the pump, the pump discharge connecting to an opening 78 inthe solenoid valve body 79. The solenoid includes a fieId'SI and a core82 which has'a valve stem or rod 83 positioned directly below whichoperates in a "bore 83'. In accordance with the movements of the valvestem 83 as will presently appear, a port 84 is opened and closed.

A passage 85 in the valve body '79 connects with the discharge 7'8 fromthe pump and this passage 85 connects with a T 87. The lower 'end of theT 87 is connected by a hose-88 toa passage 89 in a casting 91. A passage92 in the casting connects with a passage "93 formed in a part integralwith the stationary piston 67'. The casting 9 1 has a seat 94 upon whicha check valve 96 seats. A passage 97 is provided in the casting 91 whichconnects to a point above the check valve 96 and communicates with apassage 98 which connects with a port 99. A valve 101 actuated by avalve stem 102 opens and closes communication between the passage 98 andthe port 99 for a purpose which will later appear.

The upper end of the T 8'7 connects with a hose 103 which extends into arigidly secured fitting 1114 adapted to receive tubing 106. The tubing106 is adapted to carry oil under high pressure from the pump to a valveblock 107 (see Figs. 5, 6 and 7) formed in a valve block casting 107'.

Referring now to Fig. 10, for the purpose of simplifying theunderstanding of my invention 1 have made a perspective diagrammaticview of the hydraulic controls and their operation. In Fig. the valveblock has been omitted but it will be understood that the hydraulicconnections shown in Fig. 10 extend through the valve block in themanner illustrated in Figs. 9, 11 and 12. In Fig. 10 the high pressureconnection from the pump has been indicated as 106 which high pressureconnection carries oil to each of two valve assemblies 108 and 1139.

The valve block has oscillatably mounted therein two shafts 111 and 112each of which is rigidly connected as indicated at 113 to a foot pedal.Suitable bearings for these shafts are provided in the valve block 107and the valve block casting 107'. These foot pedals are designated 114and 116 and constitute the means for controlling the flow of oil to thetilt cylinder 42 (Fig. 13). It will be noted that while the shafts 111and 112 are in alignment with each other, they are separated by anintervening space 117 so that they are separately controlledrespectively by the foot pedals 114 and 116. Each of theshafts 111 and112 is provided with two sectors which constitute fiow passages aroundthe shaft. These sector flow passages are numbered 118, 119, 121 and122. In each sector a cam is provided which includes fiat spots 123 andhigh spots 124 adapted to open and close spring pressed valves such asthose indicated at 126 in Figs. 9, 11 and 12.

A conduit 127 (Fig. 13) is connected to one side end of the cylinder 42and a conduit 128 is connected to the other end of the cylinder. Theconduit 127 extends to a fitting 129 (as diagrammatically shown in Fig.10) which has a spring pressed valve at the end thereof. The conduitconnects also with a cross-over passage 131 which connects to a fitting132 which also has a spring pressed valve therein. These, valves areadapted to cooperate respectively with the cams located in the sectors119 and 122. The conduit 128 is connected to a fitting 133 which has avalve at the end thereof, the fitting being also connected to across-over passage 134 which connects with a fitting 136 which has avalve at the end thereof. These valves are opened and closed by the camslocated respectively in the sectors 118 and 121.

A conduit 137 is connected to the sump or reservoir 73 (Fig. 4) and isconnected to each of two passages 13% and 139.

When it is desired to tilt the table from the position shown in Fig. 1to that shown in Fig.2, oil is admitted to the cylinder 42 (Fig. 13) atthe left hand side of the piston 43. This is accomplished by pressingthe foot pedal 114 to rotate the shaft 111. Upon rotation of the shaft111, the cam in the sector 119 is rotated to place a high spot of thatcam in contact with the spring pressed ball valve in the fitting 1118.Oil is then admitted to the sector 119 and flows around that sector.Rotation of the cam in the sector 119 has also placed the valve in thefitting 129 in open communication with the sector 119 allowing highpressure oil to flow through the conduit 127 to the left hand side ofthe piston 43 (Fig. 13).

Rotation of the shaft 111 also places the valve in the fittings 136 inregistry with the high point of the cam in the sector 18 allowing oil toflow out of the cylinder 42 from the right hand side of the piston 43through the conduit 128, through fitting 136, around sector 118 to thefitting 138 and back to the sump through the conduit 6 137. As long asthe operator maintains his foot on the foot pedal 114, the oil flowabove described will occur until the piston 43 reaches the end of itsstroke. However, the operator may discontinue the flow of oil at anytime by releasing the foot pedal 114 which permits a spring to act onthe foot pedal, as will presently appear, to restore the shaft 111 toits normal position rotating the cams in the sectors 118 and 119 andclosing all the spring pressed valves just described. The table willthen remain in the tilted position desired by the operator thereof, theoil on opposite sidesof the piston being locked in the cylinder by theclosing of the valves.

When it is desired to restore the table to a horizontal position, thefoot pedal 116 is depressed. This action connects the high pressure line106 with the line 128 causing a flow of high pressure oil to thecylinder 42 (Fig. 13) at the right hand side of the piston 43. Thisaction also rotates the shaft 112 to.connect the conduit 127 with theconduit 137 through the sector 122 thus allowing oil to escape from theleft hand side of the piston 43 back to the sump.

As in the case of tilting movements, the operator may arrest therestoring action of the table to a horizontal position at any point bylifting his foot from the foot pedal 116 which allows a spring to rotatethe shaft 112, as will presently appear, to close the valves at anypoint prior to the table reaching the horizontal position shown in Fig.1.

' In Fig. 11, I have indicated the position of the parts with the ballsof the spring pressed ball valves inv engagement with the low points 123of the cam in the sector 119. In this position of the parts the valvesare closed. Fig. 12 is a view with the shaft 111 rotated and the springpressed valves in engagement with high points 124 of the cam in thesector 119. In this position of the parts the valves are open and highpressure oil is flowing from the high pressure line 106 through thevalve associated therewith around the sector through the valveassociated with the line 127 and through that line to the left hand sideof the piston 43 operating in the cylinder 42. It will be understoodthat sectional views through other sectors of shafts 111 and 112 wouldbe similar to Figs. 11 and 12; As shown in Fig. 9, the various sectorsare hydraulically separated from each other and leakage along theshaftsis avoided by hydraulic seals 140 located in grooves provided in theshafts 111 and 112.

Referring now to Figs. 5 to 8 inclusive, in addition to the foot pedals114and 116, foot pedals and14 6 are provided. These foot pedals extendinto a control housing 147 provided with a cover plate 148. The coverplate is provided with an elongated opening or separate slots 149 inwhich the foot pedals may operate (Fig. 7). Mounted adjacent the top ofthe control housing is a bracket 151 in apertures in which the ends ofsprings 152 are secured. Each of these springs is extended to a member153 mounted on the inner end of each of the foot pedals 114, 116, 145and146. These springs restore the foot pedalsto their normal position shownin solid lines in Fig.7 when foot pressure is released. The

valve block casting 107' extends to the right, as viewed in Fig. 6, fromthe valve block 107 and suitable bearings are provided in the castingfor the reception of a shaft 154. The arms from the valve block castingwhich carry the bearing supports for the shafts 111, 112 and 1.54amshown at 155 (Figs. 6 and 9).

The inner end of the foot pedal 145 is pinned to the shaft 154 asindicated at 156 while the inner end of the foot pedal 146 is loose onthe shaft 154.

Referring now to Fig. 6, mounted in suitable spaced bosses 158 formed inthe valve block casting is an elon gated pivot pin 157. A cradle 159pivots on the pivot pin 157 and supports a mercury switch 160. In theposition of the mercury switch 160 shown in Fig. 7, the switch is open,the cradle being normally held in this position by a spring 161 whichextends between the cradle 159 and the bracket 151. The members 153 ofeach of the foot-pedals 114, 116 and 145 has an actuating rod 163secured in an aperture thereof. Each of the rods is threaded to receivea nut 164 and each of the rods passes through the cradle 159. A lostmotion provision, indicated at 166, is made so that some movement of thefoot pedals is necessary before the nut 164 engages the cradle 159 totilt the mercury switch 160.

The mercury switch 160 is in circuit with the motor 70 and the field ofthe solenoid so that when the mercury switch 160 is tilted about theaxis of the pivot rod 157, the motor is started to supply hydraulicfluid underpressure to the system and the solenoid is energized so thatthe valve stem 83 moves down to close the escape port '84. Hydraulicfluid is then supplied to one side or the other of the cylinder 42 (Fig.13) or to the hydraulic cylinder 66 depending 'upon which of the threefoot pedals 114, 116 or 145 is depressed. When the depressed foot pedalis released, the corresponding spring 152 (Fig. 6) restores the footpedal to normal position, the mercury switch is shifted to the positionshown in Fig. 7, and the motor 70 and the solenoid 77 are deenergized.

When the solenoid 77 is deenergized, the hydraulic pressure beneathvalve stem 83 moves the valve stem and the core of the solenoid to theposition shown in Fig. 14, thereby opening the port 84. The opening ofthe bleed port 84 prevents any building up of excessive pressureparticularly when the lift cylinder reaches the end of its upwardmovement or any'movement of the table beyond the position desired whichmight result from inertia of the motor. At the same time hydraulic fluidcannot escape from the hydraulic lift cylinder 66 due to the fact thatthe check valve 96 closes and, with respect to the hydraulic cylinder42, release of either the foot pedal 114 or the foot pedal 116, as thecase may be, rotates the shaft 111 or the shaft 112 to close the valvesassociated therewith as previously described to prevent the escape ofhydraulic fluid from the cylinder 42.

Referring now to Fig. 8, as previously mentioned, the foot pedal 146 isloose on the shaft 154. Carried by a boss on the inner end of the footpedal 146 is a pin 176 which engages one arm 177 of a bell crank. Thebell crank is pivoted at 178 on a part of the valve block casting andthe other arm 179 engages the upper end of the valve stem 102 as shownat 181 (Fig. 4). Upon depressing the foot pedal 146, the pin 176 pivotsthe bell crank about the pivot 178 in a clockwise direction, as viewedin Fig. 8, to depress the valve stem and open valve 101. Opening of thevalve 101 permits oil in the hydraulic cylinder 66 to escape through theport 97, passage 98, and port 99 back to the sump or reservoir 73. Therelease of pressure in the hydraulic cylinder permits the weight of thetable to force the oil out of the hydraulic cylinder 66 to allow thetable to descend. The operator may interrupt the descent of the tablemerely by release of pressure on the foot pedal 146. Release of the footpedal allows the spring 152 to restore the parts to the normal positionand the pressure of oil below the valve 101 will close the valve so asto retain oil in the hydraulic cylinder 66 and stop descent of thetable.

One of the important aspects of my invention is the fact that wheneverthe pump is in operation, hydraulic fluid under pressure is available tothe hydraulic lift cylinder 66. It will be noted that the passage 78,88, 89 is free of valves and the check valveopens in an upward directionso that when the pump starts pressure is available to the hydraulic liftcylinder. Since the pump starts whenever any one of the foot pedals 114,116 or 145 is depressed, the ratio of the cross-sectional area of thehydraulic lift cylinder 66 with respect to the cross-sectional area ofthe tilt cylinder 42 is made such that, taking into consideration theweight of the table, the hydraulic pressure required to tilt the tableis less than that required to lift the table, Thus when "either the footpedal 114 or the foot pedal 116 is depressed, a tilting operation willoccur depending upon which foot pedal is depressed and no hydraulicfluid will be fed to the hydraulic lift cylinder until the piston 43 inthe cylinder 42 has completed its movement and the table has beenshifted to its extreme tilt position or the extreme horizontal position,depending upon whether the foot pedal 114 or the foot pedal 116 isdepressed. Since the operator releases the foot pedal either prior to orwhen the table reaches these extreme positions, no undesired action oflifting of the table will occur. However, if a tilting action is desiredin combination with a lifting action, the operator may hold his foot onthe pedal 114 until the piston 43 has completed its movement, whereuponthe continued sup ply of hydraulic fluid to the system supplies fluid tothe lift cylinder 66 to raise the table to the desired height.

The advantage of the particular arrangement above described is that itsimplifies the valving of the hydraulic system. No valve is required inthe line leading from the pump to the hydraulic lift cylinder except ofcourse the check valve 96. Moreover, no overload valving or limit switchcontrols are required at the end of piston strokes to prevent burstingof oil lines or mechanical overload damage. The elimination of suchvalves mini- Inizes sources of trouble and greatly decreases the cost ofproduction of the hydraulic system and its controls.

While I have shown and described the preferred form of my invention, itwill be apparent that various changes may be made, particularly in theform and relation of parts, without departing from the spirit of myinvention as set forth in the appended claims.

I claim:

1. A medical examination table comprising, in combination, a main tablesection, a leg rest table section, a vertically movable support, acradle pivoted to the support between its ends, pivoted adjacent one endto the leg rest section and pivoted adjacent its other end to the maintable section at a point remote from the leg rest section, meansextending between said support and the end of the main table sectionadjacent said leg rest section for supporting said end of the main tablesection, means for positioning the main table section substantiallyhorizontal and the leg rest section substantially at right anglesthereto, and means including a hydraulic cylinder connected between saidsupport and said cradle for swinging the cradle about its pivot on thesupport to simultaneously shift the main table section into an inclinedposition and the leg rest section to a position such that its edgeadjacent the main table section lies above the plane of the main tablesection while maintaining the essentially right angle relation of thetable sections.

2. A medical examination table in accordance with claim 1 in whichhydraulic means are provided for raising the level of both tablesections simultaneously.

3. A medical examination table comprising, in combination, a main tablesection and a leg rest section arranged substantially at right angles toeach other, said main table section having an end adjacent the leg restsection and an end remote therefrom and said leg rest section having anedge adjacent the adjacent end of the main table section and unconnectedthereto, a vertically extending support, a cradle pivoted to saidsupport, pivoted adjacent the remote end of the main table section andpivoted to the leg rest section adjacent said edge, an arm fixed to saidsupport at its lower end and having its upper end supporting saidadjacent end of the 'main table section but said adjacent end being freeto shift with respect thereto, and means including hydraulic meanspivoted to said support and pivoted to said cradle for shifting theremote end of the main table section downward, the adjacent end upwardand simultaneously as part of the same movement shifting the leg restsection to a position such that said edge lies above the plane of themain table section while maintaining the essentially right anglerelation of the table sections.

4. A medical examination table in accordance with claim 3 in which akneeling section is provided which may be positioned substantially atright angles to the leg rest section and means are provided foradjusting the kneeling section longitudinally of the leg rest sectionwhereby a patient may kneel on the kneeling section, bend himself at thewaist, have his lower trunk resting on said edge, his upper trunk on themain table and his abdomen relaxed and unsupported by either tablesection.

5. A medical examination table comprising, in combination, a main tablesection and a leg rest section arranged substantially at right angles toeach other, said main table section having an end adjacent the leg restsection and an end remote therefrom and said leg rest section having anedge adjacent the adjacent end of the main vtable section, a verticallyextending support, means pivoted to said support and to said tablesections for supporting the table sections for swinging movement aboutsaid support, means including hydraulic means connected between saidlast mentioned means and said support for simultaneously shifting theremote end of the main table section downward, the adjacent end upwardand the leg rest section to a position such that said edge lies abovethe plane of the main table section while maintaining the essentiallyright angle relation of the table sections, a kneeling sectionpositionable at right angles to the leg rest section and means foradjusting the kneeling section longitudinally of the leg rest section toaccommodate the leg rest section to persons of various heights whereby apatient may kneel on the kneeling section, bend himself at the waistwith his lower trunk resting on said edge, his upper trunk on themaintable section and his abdomen relaxed and unsupported by eithertable section.

6. A medical examination table in accordance with claim 5 in whichhydraulic means are provided for raising and lowering said verticallymovable support to adjust the level of both table sectionssimultaneously.

7. A medical examination table comprising, in combination, a main tablesection and a leg rest section arranged substantially at right angles toeach other, said main table section having an end adjacent the leg restsection and an end remote therefrom and said leg rest section having anedge adjacent the adjacent end of the main table section, said adjacentedge and said adjacent end being non-pivotally connected to enable saidedge and end to shift with respect to each other so thatsaid edge liesabove said end, a vertically extending support, means pivoted to saidsupport and to said table sections for supporting the table sections forswinging movement about said support, means including hydraulic meansconnected between said last mentioned means and said support forsimultaneously shifting the remote end of the main table sectiondownward, the adjacent end upward and the leg rest section to a positionsuch that said edge lies above the plane of the main table section whilemaintaining the-essentially right angle relation of the table sections.

8. A medical examination table in accordance with claim 7 in which akneeling section is provided which may be positioned substantially atright angles to the leg rest section and means are provided foradjusting the kneeling section longitudinally of the leg rest section toaccommodate patients of various heights whereby a patient may kneel onthe kneeling section, bend himself at the waist with his lower trunkresting on said edge, his upper trunk on the main table section and hisabdomen relaxed and unsupported by either table section.

9. A medical examination table comprising, in combination, a main tablesection and a leg rest section arranged substantially at right angles toeach other, said main table section having an end adjacent the leg restsection and an end remote therefrom and said leg rest section having anedge adjacent the adjacent end of the main table section, said adjacentedge and said adjacent end being non-pivotally connected to enable saidedge and end to shift with respect to each other so that said edge liesabove said end, a vertically extending support, means pivoted to saidsupport and to said table sections for supporting the table sections forswinging movement about said support, means including hydraulic meansconnected between said last mentioned means and said support forsimultaneously shifting the remote end of the main table sectiondownward, the adjacent end upward and the leg rest section to a positionsuch that said edge lies above the plane of the main table section whilemaintaining the essentially right angle relation of the table sections,and means pivoted to said first mentioned means and to said leg restsection enabling said leg rest section to be swung into co-planarrelation with said main table section.

10. A medical examination table in accordance with claim 9 in which akneeling section is provided which may be positioned substantially atright angles to the leg rest section and means are provided foradjusting the kneeling section longitudinally of the leg rest section toaccommodate patients of various heights whereby a patient may kneel onthe kneeling section, bend himself at the waist with his lower trunkresting on said edge, his upper trunk on the main table section and hisabdomen relaxed and unsupported by either table section.

11. A medical examination table comprising, in combination, a support, amain table section and a leg rest section arranged in co-planarrelation, said main table section having an end adjacent the leg restsection and an end remote therefrom and said leg rest section having anedge adjacent the adjacent end of the main table section, means pivotedto said support and to said table sections for supporting the tablesections for swinging movement about said support, an arm fixed to saidsupport at its lower end and having its upper end supporting theadjacent end of the main table section but said adjacent end being freeto shift with respect thereto and bodily with respect to said edge,means pivoted to said first mentioned means and to said leg rest sectionremote from said edge enabling said leg rest section to be swung intosubstantially right angle relation with said main table section, meansincluding said first mentioned means connected thereto and to saidsupport for simultaneously shifting the remote end of the main tablesection downward, the adjacent end upward and the leg rest section to aposition such that said edge lies above the plane of the main tablesection while maintaining the essentially right angle relation of thetable sections, a kneeling section, means for positioning said kneelingsection in coplanar or right angle relation to said leg rest section,and means for adjusting the kneeling section longitudinally of the legrest section so that patients of various heights may kneel on thekneeling section, bend himself at the waist, have his lower trunkresting on said edge with his upper trunk on the main table section andhis abdomen relaxed and unsupported by either table section, when theleg rest section is in substantially right angle relation to the maintable section.

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